172 CATALYZING INQUIRY
5.4.5 Neuroscience,
In recent years, neuroscience has expanded its horizons beyond the microstructure of the brain—
neurons, synapses, neurotransmitters, and the like—to focus on the brain’s large-scale cognitive archi-
tecture. Drawing on dramatic advances in mapping techniques, such as functional magnetic resonance
imaging (MRI) and magnetoencephalography, neuroscientists hope to give a computational account of
precisely what each specialized region of the brain is doing and how it interacts with all the other active
regions to produce high-level thought and behavior.
5.4.5.1 The Broad Landscape of Computational Neuroscience
Neuroscience seeks to probe the details of the brain and the mechanisms by which the nervous
systems develops, is organized, processes information, and establishes mental abilities. Research in
neuroscience spans many levels of organization, from atomic and molecular events on the order of one-
tenth to one nanometer, up to the entire nervous system on the order of a meter or more. In addition,
there are on the order of 10^11 neurons and thousands to tens of thousands of synapses per neuron.
Information processing in the brain occurs through the interactions and spread of chemical and
electrical signals both within and among neurons. Acting within the extensive but intricate architecture
of the neurons and their interconnections, the mechanisms are nonlinear and span a wide range of
spatial and temporal scales.^97 Understanding how the nervous system and brain work thus requires an
interdisciplinary approach to the challenging multiscale integration of experimental data, computa-
tional data, and theory.
It is helpful to describe the nervous system’s functional processes and their mechanisms at several
different levels of detail, depending on the goal of a given effort. Table 5.3 and Figure 5.12 describe the
numerous spatial and temporal scales relevant to neuroscience research, and provide some indication
of the complexity of such research.
To illustrate, a low level of analysis might involve consideration of individual neurons. In this
analysis, functional properties of neurons such as electronic structure, nerve cell connections (syn-
apses), and voltage-gated ion channels are important. At a higher level, it is recognized that individual
neurons connect in networks—an analysis at this level examines how individual neurons interact to
form functioning circuits. The mathematics of dynamic systems and visual neuroscience are notably
relevant at this level. At a still higher level, individual networks—each with its own specific architecture
and information-processing capabilities—interact to form neural nets and carry out cognition, speech
TABLE 5.3 Scales of Neuroscience ResearchSpatial Scale Component1 meter Central nervous system
10 centimeters Systems
1 centimeter Maps
1 millimeter Networks
100 microns Neurons
1 micron Synapses
10 angstroms Molecules(^97) N.T. Carnevale and S. Rosenthal, “Kinetics of Diffusion in a Spherical Cell: I. No Solute Buffering,” Journal of Neuroscience
Methods 41(3):205-216, 1992.